I figured I'd add in that, if worse comes to worst, then you can always try pulling the drive out of the enclosure and connecting it to the computer internally. If you don't know how to do that, then find someone that does.

Well, if you were going to install it internally, it would have to be on a desktop PC. I highly doubt an external enclosure is using a laptop form-factor drive. You would only be doing this to salvage the files and probably move them to a new external drive anyway.

There's also the possibility that an IDE or SATA cable (whichever this drive happens to be using) came loose inside the enclosure, actually. You may eventually have to open it up anyway.

Well... So my mom's tech guy at works thinks it's the case, because all it does it turn on for a second when I turn the power on, but that's all. So Frys sells external hard drive cases, so I'm gonna go and switch them out tomorrow. Hopefully it'll work.